JP2017055534A - Stator for rotary electric machine and rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator having a high breakdown voltage insulation system that can be operated with a high driving voltage without increasing the thickness of slot insulation paper, and a rotary electric machine in which the stator is assembled.SOLUTION: A stator for a rotary electric machine includes a stator core having plural slots formed therein, a stator coil inserted in the slot, and insulating paper inserted in the slot to insulate the stator coil and the stator core from each other. The insulating paper includes a first insulating paper portion arranged at the outside of the end surface in the slot axis direction to be adjacent to the stator core, and at least a second insulating paper portion arranged between the first insulating paper portion and the stator coil. The insulating paper forms a resin reservoir portion in which insulating resin is disposed between the first insulating paper portion and the second insulating paper portion.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a stator of a rotating electric machine and a rotating electric machine, and more particularly to a rotating electric machine mounted on an electric vehicle.

  Rotating electric machines closely related to industry and daily life are basic equipment that supports modern society. In particular, in hybrid vehicles and electric vehicles that are spreading from the viewpoint of protecting the global environment, the motor of the power source is required to be smaller and lighter from the viewpoint of securing a mounting space and improving fuel efficiency by reducing the weight.

  The slot insulation of the stator of the hybrid motor and the electric motor for the electric vehicle is made up of a slot insulating paper inserted between the stator core / coil and between the different phase coils and a fixed varnish that fills the gap and fixes the coil and the slot insulating paper to the stator core. Composed.

  In slot insulation, near the slot end of the stator core, there is a large difference in dielectric constant between the air between the slot insulation paper and the stator core and the slot insulation paper, so an electric field is generated in the air layer near the slot end. A partial discharge occurs at a low voltage between the slot insulating paper and the stator core. This partial discharge erodes the insulating layer and eventually leads to dielectric breakdown during motor operation. Therefore, in the status lot insulation of hybrid and electric vehicle power motors, it is essential that partial discharge does not occur. Yes.

  As a means for reducing the size of the power motor, it is conceivable to increase the drive voltage, but in order to cope with the increase in voltage on the extension line of the prior art, the slot insulating paper thickness is increased to correspond to the working voltage. A method for securing the insulation distance can be considered. For example, Patent Document 1 discloses a technique for adjusting the total thickness of the slot liner by multilayering according to the shared voltage.

JP 2006-60929 A

  As described above, in the method of increasing the slot insulating paper thickness and securing the insulation distance according to the working voltage, the coil space factor in the slot is reduced and the coil current is reduced. In order to make up for this point, it is necessary to increase the coil current density. However, an increase in the coil temperature is unavoidable, which may accelerate the thermal deterioration of the insulating component in the slot and impair the reliability of the insulation system.

  The present invention provides a stator having a high withstand voltage system that can withstand high drive voltage operation by reducing the electric field concentration at the end of the slot while suppressing an increase in slot insulating paper thickness, and a rotating electrical machine incorporating the stator. The purpose is to do.

  A stator of a rotating electrical machine according to the present invention includes a stator core formed with a plurality of slots, a stator coil inserted into the slot, and the stator coil and the stator core inserted into the slot. Insulating paper that insulates, wherein the insulating paper is disposed outside the end surface in the slot axial direction and adjacent to the stator core; the first insulating paper portion; and And at least a second insulating paper portion disposed between the stator coils, and the insulating paper has an insulating resin disposed between the first insulating paper portion and the second insulating paper portion. A resin reservoir is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the electric field concentration which generate | occur | produces in the space area | region near the slot edge part of a stator core can be reduced, and a small stator with a high drive voltage and a rotary electric machine using the same can be provided.

Laminated core front view used in Examples and Comparative Examples of the present invention Slot insulation paper edge bending method in embodiment 1 of the present invention Schematic diagram of shape after bending edge of slot insulating paper in Example 1 of the present invention Front view of the first embodiment of the present invention Side view of the first embodiment of the present invention FIG. 3A-A ′ enlarged cross-sectional view of the vicinity of the slot end of Example 1 of the present invention Schematic diagram of resin reservoir in Example 1 of the present invention Front view of the comparative example of the present invention Side view of the comparative example of the present invention 6B-B 'enlarged sectional view of the vicinity of the slot end portion of the comparative example of the present invention Schematic diagram of a resin reservoir in the second embodiment of the present invention Multilayer slot insulating paper in the third embodiment of the present invention Modified example of the third embodiment of the present invention

  Hereinafter, according to the results of partial discharge start voltage measurement of an insulation model in which a coil and insulating paper are incorporated in a core cut out from a stator core having an outer diameter of 245 mm, an inner diameter of 200 mm, a slot number of 72, and a core stack thickness of 94 mm, according to the invention. 1 is described. The examples and comparative examples described below are partial models of a rotating electrical machine stator, but as is obvious from the following description, it is equivalent to an actual rotating electrical machine stator.

  FIG. 1 shows a core end face shape of a stator core cut out for assembly of an insulation model. The substantially cylindrical stator core is cut into a sector shape with a central angle of 5 °, and one slot 2 is arranged at the center of the substantially sector core 1. The shape of the slot end 3 is a substantially rectangular shape with a constant width, and the width and the parallel part depth are 4.18 mm and 12.2 mm, respectively. For the laminated core, a punched electrical steel sheet equivalent to 35A300 is used. The laminated cores of the stator core are fixed with varnish, and the core is not disassembled when the sector core 1 is cut. Wire cutting was used for the cutting method of the fan-shaped core.

  In the insulation model assembly, four rectangular enamel insulated wires 7 were arranged as simulated coils 6 in the slot 2 at the center of the core 1 through the slot insulation paper 4 and 10. The simulated coil, the slot insulating paper, and the stator core in the slot were fixed with varnish. The simulated coil length was 160 mm, and the length of the simulated coil protruded 33 mm from both slot ends. The dimensions of the insulating paper were 30 mm wide and 100 mm long, and 3 mm protruded from both ends of the slot from the viewpoint of preventing creeping discharge.

  The flat enamel insulated wire 7 is formed by coating a 0.05 mm thick polyamideimide insulating layer 71 on a flat copper conductor 72 having a short side of 2.7 mm, a long side of 3.6 mm and a corner chamfer radius of 0.5 mm. Using. As the fixing varnish, a two-component mixed epoxy resin having a curing condition of 150 ° C. × 1 hour and a glass transition temperature of 125 ° C. was used. The viscosity after mixing is 0.9 mPa · s. This varnish is the same as the fixed varnish between the fan-shaped laminated cores 1.

  In the varnish fixing process in manufacturing the insulation model, the insulation model is inverted so that the simulated coil is in the vertical direction. The model was heated and held to cure the fixed varnish. Subsequently, the insulation model was turned upside down, and the fixed varnish was dropped and cured by the same method.

  Table 1 shows the insulation model configurations of the evaluated examples and comparative examples. In Examples 1 and 2, PET (polyethylene terephthalate) having a thickness of 0.1 mm and 0.05 mm, respectively, was used for the insulating paper. In Example 3, 0.05 mm aramid paper was used, and a gap between the simulated coil / core was formed. Multiple layers were formed according to the thickness of the insulating paper to minimize the thickness. In multilayering of insulating paper, a plurality of insulating papers are simply stacked, and a process for bonding the multilayered insulating papers is not performed at the time of assembling the insulating model. In each example, the end of the insulating paper was bent at the slot end in order to position the end of the insulating paper outside the end of the slot.

  In the comparative example, a three-layer laminate paper of aramid paper / PET / aramid paper having a thickness of 0.18 mm, which is an insulating paper generally used in the prior art, was used. Each layer of the laminate is bonded with a urethane adhesive. The slot end of the comparative example was straight.

  FIGS. 2A and 2B are schematic diagrams illustrating a method for bending an end portion of the insulating paper according to the first embodiment. The first insulating paper 41 adjacent to the core bent into the insertion shape in the slot and the second insulating paper 42 disposed between the first insulating paper 41 and the coil 6 are both inserted into the slot, and then at the tip. The end of the insulating paper was bent by pressing the pressing and bending die 5 provided with the taper to the slot end so that the insulating paper was not compressed and deformed, and the end of the insulating paper was arranged outside the slot end. After the insulating paper is bent at the end of the slot, the flat enamel insulated wire 7 is inserted to form the simulated coil 6.

  The slot opening side of the push-bending die 5 used in this embodiment is not tapered, but this ensures a sufficient insulation distance between the simulated coil / core on the slot opening side. Because.

  FIGS. 3A and 3B are schematic views of the front and side surfaces of an insulation model fixedly treated with the varnish of Example 1, respectively. It can be understood that the insulating paper edge of either the first insulating paper 41 or the second insulating paper 42 is located outside the slot end.

  FIG. 4 is an enlarged view of the vicinity of the slot end of the A-A ′ cross section shown in FIG. Spaces are formed between the core 1 and the first insulating paper 41, between the first insulating paper 41 and the second insulating paper 42, and between the second insulating paper 42 and the enamel insulating layer 71 of the simulated coil 6. Yes. The concentration of the electric field at the end of the core that causes a decrease in the partial discharge start voltage is reduced by generating an electric field in a space divided by a plurality of insulating papers formed between the coil conductor 72 and the core 1.

  FIG. 5 is an enlarged schematic view of the space between the first insulating paper 41 and the second insulating paper 42 in FIG. It was confirmed that the fixed varnish was filled in such a manner that the first insulating paper 41 and the second insulating paper 42 were connected with the crossing line as the bottom, and the varnish reservoir 8 was formed. By this varnish accumulation, the insulation distance between the conductor coil and the core, which must be noted in the insulation design in the slot end insulation, can be increased, and as a result, the electric field is reduced. It was confirmed that such a varnish reservoir was formed in any of the other examples.

  6 and 7 show the form of an insulation model manufactured as a comparative example for the purpose of comparison with FIGS. 3 and 4. From the comparative example of FIG. 7, which is an enlarged cross-sectional view in the vicinity of the BB ′ slot end of FIG. 6A, the three-layer laminated conventional insulating paper 10 and the core 1 are formed between the coil conductor 72 and the core 1. There is a continuous space, and the electric field concentrates in the air layer near the slot end due to the dielectric constant difference between the conventional insulating paper and air. Although not shown in the drawings, the fixed varnish permeates between the examples in Table 1, between the simulated coil and insulating paper of the insulation model manufactured as a comparative example, between the insulating paper and the core, and between the multilayer insulating papers of the examples. It is confirmed that the slot components of each insulation model are fixed with varnish.

  Table 2 shows the measurement results of the partial discharge start voltage at 50 Hz of the insulation model manufactured as an example and a comparative example shown in Table 1. The partial discharge start voltage is a result of measurement by grounding the core 1 of each insulation model and applying a voltage to the simulated coil 6, and the voltage at which the partial discharge charge amount reached 100 pC was defined as the partial discharge start voltage. The measured values in Table 2 are shown as average values obtained by measuring five times in each example and comparative example.

  An aluminum conductive adhesive tape was wound twice around the core back portion of the core 1, and a grounding cable was attached and fixed thereon with a conductive tape. For the simulated coil 6, the enamel insulation layers 71 at both ends of the four flat enamel insulation wires 7 are removed with a width of about 10 mm, the conductor 72 is exposed, an aluminum foil is wound around that portion, and an aluminum foil electrode on one side A power cable was attached. The formation of the core-side ground electrode and the simulated coil voltage-applying electrode was carried out before the varnish was fixed. The formed electrode was covered with a Teflon (registered trademark) adhesive tape to prevent the varnish from adhering when the varnish was fixed, and the coated tape was removed after fixing.

  From Table 2, the partial discharge start voltage is about 1.06 kVrms in the prior art, whereas in the examples of the present invention, the partial discharge start voltage is increased in any of the examples. We were able to verify. Further, the partial discharge start voltage is higher in Examples 2 and 3 than in Example 1, and by increasing the number of layers, the number of spaces formed between the insulating papers and the volume of the varnish reservoir increased. It is.

  In this example, the effect was verified using PET and aramid paper, but the insulating resin sheet that can be used in the present invention is not limited to PET or aramid paper. Understood.

  Next, a second embodiment of the present invention will be described with reference to FIG. A room temperature-curing type silicone resin having a viscosity of 0.6 Pa · s was filled at both ends of the insulating paper of the insulation model manufactured in Example 1 of Table 1, and the effect was verified. FIG. 8 is an enlarged schematic view of the vicinity of the intersection line 9 between the first insulating paper 41 and the second insulating paper 42 after filling and curing the silicone resin. A second resin reservoir layer 11 is newly formed on the fixed varnish reservoir layer 8 which is the first resin reservoir layer.

  When the partial discharge start voltage after the additional filling of the silicone resin was measured in the same manner as in Table 2, when there was no second resin reservoir and only the fixed varnish reservoir as the first resin reservoir, as shown in Table 2. The partial discharge start voltage, which was 1.28 kVrms, could be increased to 1.62 kVrms, and the effect of forming the second resin pool could be confirmed.

  In the second embodiment of the present invention, the second resin reservoir is formed of a silicone resin as described above, but the second resin reservoir forming resin that can be used in the present invention is not limited to a silicone resin.

  Further, in the second embodiment, the effect is explained by examples formed with different resin reservoirs. However, the resin varnish is not formed by the first adhesive varnish, but the adhesive varnish penetrates and the in-slot component is formed. Even in the case of fixing, the resin pool can be formed between the coil / insulating paper, between the core / insulating paper, and between the multilayer insulating paper by using the second resin pool forming method described above.

  FIG. 9 shows another embodiment relating to the formation of multilayer insulation paper in the present invention. In the example of Table 1, an insulation model was manufactured with a simple laminated structure that is not bonded to each other. In Table 1, there was no situation where the fixing varnish permeated between the multilayer insulating papers and the fixing property of the insulating component in the slot was impaired. Since it is difficult for the fixed varnish to penetrate between the insulating papers, it is necessary to join the multilayer insulating papers in advance.

  FIG. 9 shows an embodiment implemented for this purpose, and shows a method of forming the multilayer insulating paper 12 when the insulating paper configuration of Example 2 in Table 1 is used. After stacking 0.05 mm PET sheets 13 cut to a predetermined size and stacked, the parts disposed in the slots are ultrasonically bonded in a form perpendicular to the slot axis. Each layer is fixed by ultrasonic bonding. After ultrasonic bonding, bending processing for slot insertion is performed, and after insertion of the slot, the non-bonded multilayered layer at the end of the slot is pushed and bent in the same manner as in the second embodiment by the method of FIG. An insulation model serving as an example was manufactured, and the partial discharge start voltage was measured in the same manner as in the above method. The fixing varnish treatment after insertion of the flat enamel insulated wire of the simulated coil is the same method as in the second embodiment.

  The partial discharge start voltage was 1.65 kVrms, which was higher than the measurement result of Example 2 shown in Table 2. This is presumably because the ultrasonic bonding portion 14 existing perpendicular to the slot axis direction dams up the fixed varnish, so that the varnish accumulation volume is increased from that in the second embodiment.

  In FIG. 9, the ultrasonic bonding portion 14 is provided in a straight line perpendicular to the slot axis, but the same effect can be obtained with the embodiment shown in FIG. 10. FIG. 10 is a schematic diagram when the multilayer insulating paper 15 is spot-bonded 16 by ultrasonic waves.

  In the third embodiment, which describes the joining of multi-layer insulating paper, ultrasonic bonding is used as the bonding method. However, high-frequency bonding, thermal fusion bonding, or adhesive bonding by partial application of an adhesive is used. Can do.

  In this embodiment, since the insulation model was produced, ultrasonic insulation was performed after stacking the cut insulation paper. However, in the case of mass production of the stator core using the present invention, it is joined at predetermined positions and intervals according to the slot length. The multilayer insulating paper wound up in the form of a rolled roll can be cut and used.

  The present invention provides a high partial discharge starting voltage at the end of a stator core slot, which is implemented for the purpose of developing a high withstand voltage insulation system corresponding to downsizing and high driving voltage of high power density motors such as hybrid vehicles and electric vehicle drive motors. It was obtained as a result of diligent examination of the conversion. The present invention has found that electric field concentration in the vicinity of the stator core is reduced by multilayering the slot insulating paper installed between the coil / stator core in the vicinity of the slot end of the stator core and forming a resin reservoir between the multilayer insulating paper. It came.

  At the slot end of the stator core, due to the dielectric constant difference between the insulating paper of the slot insulating paper and the stator core, the electric field is concentrated on the air layer near the slot end, and it is difficult to increase the partial discharge start voltage. Therefore, the partial discharge start voltage can be increased by reducing the electric field concentration at the end of the stator core.

  As a means for this, in the present invention, the slot insulating paper in the vicinity of the slot end is multilayered to divide the space between the slot insulating paper and the stator core that causes electric field concentration, thereby relaxing the electric field concentration in the vicinity of the slot end. In addition, by forming a resin reservoir between the multilayered insulated paper, the electric field between the coil and the core is reduced, and as a result, the electric field concentration near the slot end can be greatly reduced, and high partial discharge is started. Voltageization is possible.

1: Core 2: Slot 3: Slot end 4: Slot insulating paper 41 of Example 1: First insulating paper 41: Second insulating paper 5: Push-bending die 6: Simulated coil 7: Flat enamel insulated wire 71: Polyimide insulating layer 72: Copper conductor 8: Varnish reservoir 9: First and second insulating paper intersecting lines 10: Comparative slot insulating paper 11: Second resin reservoir 12: Bonded multilayer insulating paper 13: PET sheet 14: Ultrasonic bonding portion 15: Another form of bonding multilayer insulating paper 16: Spot ultrasonic bonding portion

FIG. 1 shows a core end face shape of a stator core cut out for assembly of an insulation model. The substantially cylindrical stator core is cut into a sector shape with a central angle of 5 °, and one slot 2 is arranged at the center of the substantially sector core 1. The shape of slot section 3 is a constant width substantially rectangular, its width, the parallel portion depth, respectively 4.18, is 12.2 mm. For the laminated core, a punched electrical steel sheet equivalent to 35A300 is used. The laminated cores of the stator core are fixed with varnish, and the core is not disassembled when the sector core 1 is cut. Wire cutting was used for the cutting method of the fan-shaped core.

In varnish fixing process in the insulating model fabrication, simulated coil is inverted insulation model such that the vertical direction, the solid adhesive varnish not a or poured into a dropping and the slot from the insulation sheet edge upward, raising insulation model to a predetermined temperature The adhesive varnish was cured by maintaining the temperature. Subsequently, the insulation model was turned upside down, and the fixed varnish was dropped and cured by the same method.

Claims (6)

A stator core formed with a plurality of slots;
A stator coil inserted into the slot;
In the stator of the rotating electrical machine, including the insulating paper that is inserted into the slot and insulates the stator coil and the stator core,
The insulating paper is disposed outside the end surface in the slot axial direction and adjacent to the stator core, and is disposed between the first insulating paper portion and the stator coil. And at least a second insulating paper portion,
The insulating paper is a stator of a rotating electrical machine in which a resin reservoir portion in which an insulating resin is disposed is formed between the first insulating paper portion and the second insulating paper portion. The stator of the rotating electrical machine according to claim 1,
A stator of a rotating electrical machine in which an axial end portion of the second insulating paper portion is disposed closer to the stator coil than an axial end portion of the first insulating paper. In the stator of the rotating electrical machine according to claim 1 or 2,
The said resin reservoir part is a stator of the rotary electric machine which has the 1st resin reservoir part by which the fixed varnish is arrange | positioned, and the 2nd resin reservoir part formed on the said 1st resin reservoir part. In the stator of the rotating electrical machine according to any one of claims 1 to 3,
A stator of a rotating electrical machine in which the first insulating paper portion and the second insulating paper portion have a joint portion inside the slot. In the stator of the rotating electrical machine according to any one of claims 1 to 4,
The stator coil is a stator of a rotating electric machine composed of segment windings constituting one turn. A stator for a rotating electrical machine according to any one of claims 1 to 4,
A rotating electrical machine comprising: the stator and a rotor disposed through a predetermined gap.

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